> > > > i wonder if gcc can auto-vectorize scalar sincos > > calls, the vectorizer seems to want the calls to > > have no side-effect, but attribute pure or const > > is not appropriate for sincos (which has no return > > value but takes writable pointer args) > > We have __builtin_cexpi for that but not sure if any of the mechanisms can > provide a mapping to a vectorized variant. >
1. Using flags -fopt-info-all and -fopt-info-internals, the failure to vectorize sincos is reported as "unsupported data-type: complex double". The default GCC behavior is to replace sincos calls with calls to __builtin_cexpi. 2. Using flags -fno-builtin-sincos and -fno-builtin-cexpi, the failure to vectorize sincos is different. In this case, the failure to vectorize is due to "number of iterations could not be computed". No calls to __builtin_cexpi; sincos calls retained. Questions: 1. Should we aim to provide a vectorized version of __builtin_cexpi? If so, it would have to be a PPC64-only vector __builtin-cexpi, right? 2. Or should we require that vectorized sincos be available only when -fno-builtin-sincos flag is used in compilation? I don't think we need to fix both types of vectorization failures in order to obtain sincos vectorization. Thanks. Bert.
